The present invention relates to a fan selection method and a fan selection device for selecting a fan required for use in cooling an inside space of a housing with an electric device that generates heat included therein.
Japanese Patent Application Laid-Open Publication No. 246728/2004 discloses a method and a system for computing a proper level of each of a plurality of fans having different performances when mounted in an electronic device based on fan data, and determining ranking of fan candidates to be mounted in the electronic device based on a parameter for each of the fans obtained by this computation. Specifically, specifications covering an amount of heat in a heating element within the electronic device, an allowable temperature rise value of a housing that includes the electronic device, and the like are first determined. Next, a required flow quantity of the fan for cooling an internal temperature of the housing to within an allowable temperature is computed. When the required flow quantity is computed, no particular consideration is given to the size of an air vent provided at the housing. Then, PQ curves each indicating a static pressure and a flow quantity of each fan and output curves of the fans are plotted. When the PQ curves and the output curves are plotted, a ventilation resistance is determined from each PQ curve, an impedance curve for the device including each of the fans is plotted from this ventilation resistance, and then the operating point of each fan is determined from the impedance curve and the PQ curve. If a ventilation resistance when each fan is operated matches the ventilation resistance of the housing of the electric device, it is determined that the fan operates in the electronic device with no problem. Then, from each plotted output curve, the flow quantity at the time of the maximum output of each fan is computed as the parameter. Finally, the required flow quantity is compared with the flow quantity at the time of the maximum output of each fan, thereby selecting a fan to be mounted in the electric device.
In a conventional technique, based on the plotted curves, a designer himself can see why the unselected fans have not been set. In the conventional technique, however, no particular consideration is given to the size of the air vent at the housing. Thus, a housing structure difference may cause an error in the fan selection. Further, in order to plot the static pressure-flow quantity curve or the PQ curve and the output curve, detailed data on each of the fans needs to be prepared. Further, specifically, a rather complicated computation such as the computation for obtaining the impedance curve for the electric device including each of the fans is required. For this reason, in the conventional technique, it is necessary for the designer of the electronic device to determine design conditions in detail. As described above, in the conventional technique, the data on the fans must be prepared in advance in detail, and it needs time and effort to perform inputting or updating of the fan data. Further, since the complicated computation is necessary for the fan selection and plotting the PQ curves, output curves, and impedance curve, the fan selection cannot be performed readily. In the conventional technique, unless some conditions about the fan selection have been determined, the fan selection cannot be performed readily.